Developers often search Google for reference code. Whereas Google search returns generic results there is a specialized tool for this purpose. Ohloh Code Search is a high performance open source code search engine. You can search code with numerous criteria and it returns you the results instantly. Features:
- Search 21,280,539,120 lines of open source code
- Search criteria like classes or structures whose name contain, compound searches, exact matches and so on
- Filter results by definition (function, class, field…), project, language or file extension
- Clean interface, easy navigation between results
Code Search uses the enterprise standard Code Sight indexing and search engine under the hoods. If you want to use Code Sight locally you can download the free and limited to 200K lines of code edition from here.